Appendix C: Network Planning and Configuration

NOTE

Losses introduced by connections at punch-down blocks and other equipment reduce total segment length. For each connector or patch panel in the link, subtract 12 meters from the total length of your cable.

Insertion Loss - Between frequencies of 5.0 and 10.0 MHz, the maximum insertion loss must not exceed 11.5 dB. This includes the attenuation of the cables, connectors, patch panels, and reflection losses due to impedance mismatches in the link segment.

Impedance - Cabletron Systems 10BASE-T Twisted Pair products work on twisted pair cable with 75 to 165 ohms impedance. Unshielded twisted pair cables typically have an impedance of between 85 to 110 ohms. You can also use shielded twisted pair cables, such as IBM Type 1 cable, but keep in mind that this cable has an impedance of 150 ohms. The high impedance of the IBM Type 1 cable increases signal reflection. However, due to cable shielding, and its subsequent lack of crosstalk between shielded pairs, this signal reflection has little effect on the quality of the received signal.

Jitter - Intersymbol interference and reflections can cause jitter in the bit cell timing, resulting in data errors. 10BASE-T links must not generate more than 5.0 ns of jitter. Make sure your cable meets 10BASE-T link impedance requirements to rule out jitter as a concern.

Delay - The maximum propagation delay of a 10BASE-T link segment must not exceed 1000 ns. This 1000 ns maximum delay limits the maximum link segment length to no greater than 200 meters.

Crosstalk - Signal coupling between different cable pairs within a multi-pair cable bundle causes crosstalk. 10BASE-T transceiver design alleviates concerns about crosstalk, providing the cable meets all other requirements.

Noise - Crosstalk, or externally induced impulses, can cause noise. Impulse noise may cause data errors if the impulses occur at very specific times during data transmission. Generally, noise is not a concern. If you suspect noise-related data errors, you may need to reroute the cable or eliminate the source of the impulse noise.

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NBR-SERIES Installation Guide

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Cabletron Systems NBR-220, NBR-420, NBR-620 manual C-2 NBR-SERIES Installation Guide

NBR-620, NBR-220, NBR-420 specifications

Cabletron Systems, a well-known name in the networking field, has designed a range of network interface devices including the NBR-620, NBR-220, and NBR-420 models. These devices have become essential components for businesses looking to enhance their network performance and reliability.

The NBR-620, for instance, is a high-performance network bridge/router that specializes in managing network traffic efficiently. It offers a robust set of features such as multiple Ethernet ports, which can support various data rates, including 10/100/1000 Mbps, making it ideal for both small and large enterprises. The NBR-620 supports advanced routing protocols like OSPF and RIP, which optimize data path selection and ensure effective communication across different network segments. Moreover, its built-in firewall capabilities provide an additional layer of security, safeguarding sensitive data from potential threats and unauthorized access.

The NBR-220, on the other hand, is designed for cost-effective solutions without compromising on essential functionalities. This device supports simple plug-and-play installation, making it user-friendly for organizations that may not have an extensive IT infrastructure. The NBR-220 includes features such as VLAN support, allowing for network segmentation and increased security. Its scalability means that it can grow alongside an organization's needs, accommodating future expansions efficiently. The device's ability to support multiple network topologies ensures versatility in deployment, catering to various business requirements.

Finally, the NBR-420 is a versatile networking solution that combines the best elements of the previous models but with enhanced features suitable for demanding enterprise environments. It includes advanced quality of service (QoS) capabilities, ensuring that critical applications receive the bandwidth they require for optimal performance. With support for IPv6, the NBR-420 prepares businesses for the future of networking as the world transitions more towards this next-generation internet protocol. Additionally, its built-in diagnostics tools facilitate easy monitoring and management of network performance.

In summary, Cabletron Systems' NBR-620, NBR-220, and NBR-420 offer diverse solutions tailored for modern networking needs. Each model encompasses unique features and technologies that cater to various business sizes and requirements, focusing on performance, scalability, and security. As businesses continue to evolve in a digital-first world, these devices play a crucial role in facilitating seamless network operations.